Optodes are chemical sensors that respond to the presence of an analyte (e.g., oxygen, protons (pH), sodium, potassium, glucose, or the like) with a detectable change in an optical characteristic. With the development of improved imaging techniques, optodes now provide a viable alternative to electrode-based sensors and more complicated analytical instrumentation. However, even as imaging techniques improve, the detection of the change in the optical characteristic can be marred by background physical interferences.